What is Tesla PowerWall+ (Plus)? • Solar Electric Contractor In Seattle WA | (206) 557-4215

The home battery marketplace is growing fast with new products, but the Tesla PowerWall still makes up over 60% market share of the entire industry. What makes Tesla’s new inverter + battery product PowerWall+ unique? In this article, we dive into the PowerWall+ product, and how to decide if a solar battery in general, and PowerWall+ specifically, is the right option for your home and energy goals. 

What is PowerWall+?

PowerWall+ is a combination of a 7.6kW Tesla string inverter and a 13.5kWh Tesla PowerWall 2 battery preassembled as one unit. By packaging the two components together, you get some distinct advantages that we discuss below: lower equipment costs; increased maximum discharge rate of the battery; and streamlined installation process, as we discuss below. 

What makes PowerWall+ different from PowerWall 2?

PowerWall+ (Plus) is a DC-coupled battery backup system. This means only one inverter is needed to integrate the battery with the rest of the solar PV system. PowerWall+, therefore, replaces a traditional string inverter on older solar PV systems and replaces a second inverter in new installations. Because the inverter is integrated, the PowerWall+ inverter controls the battery charge and discharge rates more directly, giving the system more capacity and flexibility.

PowerWall 2, on the other hand, is AC-coupled, meaning its functionality is limited to the capabilities of the existing solar PV inverter. 

 Who benefits most from PowerWall+?

PowerWall+ is often the best backup option on new solar installations for homes with less shading. One drawback of PowerWall+ is that the string inverter does not optimize the solar production of each individual solar module, but rather ties several modules together into a “string”. If one of the modules is in the shade, that whole group (or string) of modules will be affected. This makes PowerWall+ less ideal with complex roofs or roofs that have a lot of intermittent shading. 

As a battery retrofit of an existing solar PV system, your best option is PowerWall 2 because you will not have to replace or modify any of the existing equipment.

Another limit of PowerWall+ is the inverter only comes in one size: 7.6kW. This means that if you want more than, say, 10,000W of solar on the roof, you are going to need more than one inverter. If you add a second inverter that is stand-alone, any solar connected to it will not be feeding you’re your electrical system in a power outage. The biggest struggle we have with designing with PowerWall+ is the inverter sizing limitations.

 What are the benefits of PowerWall+ over other home batteries?

  • Lower material costs: An inverter typically represents a sizeable chunk of the overall solar PV system installation cost. When bundled with PowerWall, the Tesla inverter is less than half the cost of comparable inverters on the market.
  • Lower labor costs: The Tesla inverter comes prewired to the battery. Wiring an inverter to a battery typically takes hours of labor for an electrician to accomplish. Commissioning PowerWall+ also takes about half the usual work because the components were developed for each other.
  • Better Performance in Outages: PowerWall 2 has a 5.8kW battery discharge limit in power outages because it does not control the existing inverter, while the PowerWall+ has a 9.6kW max discharge limit. This means PowerWall+ can back up about 16 amps more than PowerWall 2.
  • Highest Load Start capability: Traditionally, well pumps and other motors that require a high load start capability (LRA) to turn on was an Achilles heel for battery backup systems. PowerWall+, on the other hand, has a whopping 98A LRA for each PowerWall. This means almost any motor will start in an outage with just one battery.
  • Better Aesthetics: In true Tesla fashion, a lot of thought and care has gone into the looks of PowerWall+. The packaging is sleek and clean compared to other options on the market, making PowerWall+ a good option even if the battery is being installed near the entrance of the home.

 How Much Does PowerWall+ Cost?

For any home battery options, the majority of the cost is in the equipment itself. While the cost of adding a battery is heavily dependent on on-site specifics, a straightforward PowerWall+ installation is typically going to add around $13k to a comparable 10kW grid-tied solar PV system. For battery backup retrofits, a PowerWall 2 could add $19k or more to the project, depending on the complexity of installation. Details are important, so if you are interested in getting solar + storage or retrofitting your existing solar PV system, make an appointment with one of our solar experts. 

 Where can PowerWall+ be installed?

PowerWall+ can be installed inside the home in non-living spaces such as the garage or mechanical room. It can also be installed outside the home, although we recommend building a bump-out around the battery to give it some protection and insulation. Batteries will always perform better in conditioned spaces.

Contact us today to find out if PowerWall+ is right for you.

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